I have been using FireFox to talk directly to my cameras. As of 3/7/2017, the new release of Fierfox (52.0) rejects plugin's and you can't get past the sign-on screen. I have discovered if you go back to the previous release (51.0.1), everything works fine.
I see where someone posted in January that the Beta FireFox had this issue... now that it's public it effects everyone unless you downgrade firefox.
The browsers you can use to directly address the cameras by I.P. are getting non-existant. Any thoughts or ideas?
Thanks Skip

I had the same problem. But following the instructions in your file : How to allow plugin run on my Firefox 52 for my Foscam camera or NVR ? Now it's ok.

But I do not like that sentence at the end of the document :
''''' Note, with Firefox 53, the ability to restore NPAPI plugin support will be removed completely.
We suggest you use Internet Explore to access cameras for more stable experience and performance.'''''''

You could follow the evolution of the versions of firefox. Which is used by several thousand people

Foscam better fix this damn Firefox issue quick smart. Saying to use IE is a lame and stupid response.
If we wanted to use IE then we would NOT be using Firefox.
People using an alternate browser to IE do so for a reason.

Foscam, times are moving forward you need to too!

In saying that, Mozilla should still allow the option for the customer to decide. If they want to have the plugin in enabled, then it should be their choice.

Just ran into this issue. This stinks, as Firefox is my regular browser. It appears that this release has dropped support for the API that the IPCam plugin uses in Firefox 52. They claim that it is no longer needed. Sounds like Foscam will need to update their FW if they wish to maintain support in Firefox.

Will try one of the work around for now - but do hope that the Foscam Engineers are aware of this and are working it.

I have tested the Foscam cameras working on Firefox 52.0 32-bit version. Please download the attachment to install into computer, then please clean the browser caches, then please try to login the camera. Thank you.

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I've just tried installing it, going to Tools > Options > Advanced > Network > Cached Web Content > Clear Now but I can't get the plug in to work (Win10 x64, Firefox 52.0 32-bit). Any ideas or do I have to do something different to clear the cache?

i have also problem
firefox 52 ..
foscam 9900
Plugins are not found, Click me to download, because firefox is stop support of NPAPI
Chrome is working with plugin
Microsoft IE EDGE dont support
IE 11 on windows 10 .. dont work also.. no plug in
i have installed lasted 3.3.0.31

i have this same issue i only use firefox as well i have 3 fi9803's and Firefox is telling me the add on is corrupt. i have tried all of the work arounds and none seem to work. foscam can you please fix this issue with firefox

i have an 64Bit Win7. IPCWebComponents installed in Programme (x86). And i will work with an older Version Firefox (V47/32Bit) as portable Version. But ... i cant work with my Foscam! Where is the plugins.xpi? to install in FF?